Kit - RMS900-108980Updated 3 hours ago
RMSTATOR RMS900-108980 – Yamaha YZ250 1999–2024 Installation Guide
This guide explains how to install the RMSTATOR RMS900-108980 kit on a 1999–2024 Yamaha YZ250. The kit converts the motorcycle to a fully DC-powered 150W charging and ignition system. The battery is not included.
Before You Begin
A 12V battery is required. Do not use a capacitor. The system can operate with different battery capacities, but a battery is necessary to ensure reliable starting.
The CDI is now powered by the battery. After each time you stop the engine, turn the red CDI ignition switch to OFF. Otherwise, the CDI will continue drawing power from the battery and may drain it completely.
The original engine kill switch can still be used to stop the engine, but it does not replace the red CDI switch for shutting off its power supply.
Plan a mounting location for the battery and both voltage regulators. The recommended location is inside the airbox.
Suggested Batteries for the Airbox
Antigravity AG-401 (6 Ah) or AG-801 (11 Ah): AG-401 and AG-801.
EarthX ETZ5G (3.4 Ah): EarthX ETZ5G.
Suggested Battery Mount
RMSTATOR recommends the Fisch Moto battery bracket for the YZ250: Battery Bracket. The Fisch Moto Electric Starter Kit is also available.
Installation
1. Remove the Original Components
Remove the seat, gas tank shrouds, gas tank, and airbox side panels to access the components.
Disconnect the 6-pin stator wiring harness connector.
Remove the stator cover by removing its 8mm bolts.
Remove the flywheel using the included puller.
Remove the original stator by removing its three Phillips-head screws.
2. Install the New Stator
Install the new stator in the original OEM location.
Apply red threadlocker to the mounting bolts.
Install the grommet, then route the wires and connector as they were originally installed.
3. Reinstall the Flywheel
Reinstall the flywheel. Make sure the woodruff key is installed on the crankshaft and that the flywheel is correctly aligned.
Torque the flywheel nut to 40 ft-lbs.
Reinstall the stator cover.
4. Reconnect the Stator Connector
Connect the new stator's 6-pin connector, which contains three wires (Black, White/Red, and White/Blue), to the factory wiring harness.
Leave the other 6-pin connector, which contains two Yellow wires and two White wires, disconnected for now. It will be used in Step 6.
5. Choose the Battery and Regulator Mounting Location
Choose a mounting location for the battery and both voltage regulators. The recommended location is inside the airbox.
The manufacturer's example uses an Antigravity AG-801 battery and a Fisch Moto mounting bracket positioned above the air filter.
6. Install the Charging Harness
Route the charging harness along the frame toward the airbox.
Connect the charging harness to the stator's 6-pin connector containing two White wires and two Yellow wires, located under the gas tank.
Connect the Red and Black wires with ring terminals directly to the corresponding battery terminals.
Connect the two 4-pin harness connectors to the matching voltage regulator connectors. Either connector can be connected to either regulator.
7. Install the CDI and Prepare Its Connector
This step is critical. Read it completely before beginning the installation.
Disconnect and remove the original CDI box located on the right side of the frame neck.
Locate the original 16-pin CDI connector. Remove its Yellow locking piece.
Using a depinning tool, small pick, or small screwdriver, carefully lift the Black plastic locking tab for each wire listed below, then pull the wire out through the back of the connector.
The original 16-pin connector will no longer be used. Tuck it into the empty triangular area under the frame, behind the steering neck.
Insert the removed wires into the included 6-pin connector. Orient the connector by looking at its back, with the locking tab facing upward. Use the following table to identify the left, center, and right positions.
| Row | Left | Center | Right |
|---|---|---|---|
| Upper Row | White/Red | White/Blue | No Wire |
| Lower Row | Orange | Black | Black/White |
Functions of the wires removed from the original connector:
White/Blue and White/Red: Pickup Coil
Orange: Ignition Coil Output
Black: Ground
Black/White: Engine Kill Switch (ground to kill spark)
Install the new CDI box in the original rubber boot and secure it using two large zip ties.
Route the wires and connectors behind the radiator.
Connect the CDI's 6-pin connector to the newly wired 6-pin connector.
Leave the CDI's Red wire connector disconnected for now. It will be used in Step 9.
8. Install the Handlebar Switch
Install the switch on either the left or right side of the handlebars, then route its wiring harness toward the center.
Attach the switch's ground ring terminal to the frame wire bracket.
9. Install the Handlebar Wiring Harness
Connect the handlebar switch to the matching 6-pin connector on the harness.
Route the harness along the frame backbone toward the airbox.
Connect the Red wire from the harness to the Red wire from the CDI box. This connection supplies battery power to the CDI when the switch is ON.
Route the harness into the airbox. Connect the Red (+) and Black (-) ring terminals to the corresponding battery terminals.
Attach the single Black wire ring terminal to a clean frame bolt inside the airbox.
The lighting output wires controlled by the handlebar switch are now available at the front of the motorcycle:
Blue: Running light (+12V available in HI or LOW position).
Green: Low beam light output.
Yellow: High beam light output.
10. Check and Secure the Wiring
Check all connections and secure the wires to the frame using zip ties. Make sure no wires rub against other components or become stretched when turning the handlebars.
Operation
Lighting Switch
OFF: No power output from the front harness wires.
LOW: The Green wire (low beam) and Blue wire (running light) provide +12V.
HIGH: The Yellow wire (high beam) and Blue wire (running light) provide +12V.
Each light must also be grounded to the frame to complete the circuit. RMSTATOR recommends using LED lights.
CDI ON/OFF Switch
Right Side: CDI power OFF.
Left Side: CDI power ON. The LED indicator illuminates when CDI ignition power is activated.
IMPORTANT: Move the red CDI switch to the RIGHT/OFF position every time you stop the engine. Move it back to the LEFT/ON position before starting the engine.
Dual-Sport Use
You can add a dual-sport lighting kit powered directly from the battery. The supplied handlebar lighting switch and harness can be removed.
To power the ignition, the CDI's Red wire must receive a switched +12V power supply that allows CDI power to be turned ON and OFF.
Connect all other accessories directly to the battery terminals and protect each accessory with a separate fuse.
Adding a battery charger connector can help maintain the battery in good condition when the motorcycle is not in use.
Electrical Wiring Diagram Reference
High Beam: Yellow wire; the light must be grounded.
Low Beam: Green wire; the light must be grounded.
Running Light: Blue wire; +12V in HI and LOW positions.
Handlebar Switch: Controls HI/LOW/OFF lighting functions.
Ignition Switch: Controls ignition ON/OFF.
CDI: +12V CDI power supply.
Original Engine Kill Switch: Grounds the ignition circuit to stop the spark.
Ignition Coil: Output to the ignition coil and spark plug wire.
Pickup Coil: Two pickup coil wires connected to the CDI.
Stator: Charging Coils 1 and 2.
Regulators: Two separate voltage regulators.
Battery: Positive (+) and Negative (-) terminals.
Ground: Stator ground and frame ground.
The diagram shows the CDI connected to the ignition coil and spark plug, the pickup coil connected to the CDI, the two stator charging coils connected to separate voltage regulators, and the regulators connected to the battery.
Once the installation is complete, enjoy your new 12V 150W charging system on your YZ250!